Search results
Results From The WOW.Com Content Network
Trophozoites adhere to host epithelial cells via a specialized disk-shaped organelle called the ventral disk. [14] Cysts are oval-shaped cells slightly smaller than trophozoites. [15] They lack flagella, and are covered by a smooth, clear cyst wall. [15] Each cyst contains four nuclei and fragments of the ventral disc. [15]
Less common symptoms include vomiting and blood in the stool. [1] Symptoms usually begin one to three weeks after exposure and, without treatment, may last two to six weeks or longer. [4] Giardiasis usually spreads when Giardia duodenalis cysts within faeces contaminate food or water that is later consumed orally. [1]
Giardia (/ dʒ iː ˈ ɑːr d i ə / or / ˈ dʒ ɑːr d i ə /) is a genus of anaerobic flagellated protozoan parasites of the phylum Metamonada that colonise and reproduce in the small intestines of several vertebrates, causing the disease giardiasis. Their life cycle alternates between a swimming trophozoite and an infective, resistant cyst.
Giardiasis is a disease of the small intestine caused by a protist parasite Giardia lamblia. This does not spread but remains confined to the lumen of the small intestine. [47] It can often be asymptomatic, but as often can be indicated by a variety of symptoms. Giardiasis is the most common pathogenic parasitic infection in humans. [48]
Gastrointestinal conditions include inflammation of the small and/or large intestine, diarrhea/dysentery, abdominal pains, and nausea/vomiting. These symptoms negatively impact nutritional status, including decreased absorption of micronutrients, loss of appetite, weight loss, and intestinal blood loss that can often result in anemia.
They include Giardia duodenalis, which causes giardiasis in humans. [3] They are placed among the metamonads , and appear to be particularly close relatives of the retortamonads . Morphology
The gut-associated lymphoid tissue lies throughout the intestine, covering an area of approximately 260–300 m 2. [5] In order to increase the surface area for absorption, the intestinal mucosa is made up of finger-like projections (), covered by a monolayer of epithelial cells, which separates the GALT from the lumen intestine and its contents.
No one knows how D. fragilis is spread; one possibility is from swallowing contaminated water or food. Many people who are infected with this parasite show no signs of being infected. Sometimes the infection can be observed; the most common symptoms include diarrhea, stomach pains, loss of appetite, nausea, and fatigue. [11]